The evaluation of the overall thermal comfort inside a vehicle

Abstract

The thermal comfort is one of the most important aspects of the modern vehicles that can influence the safety, the fuel consumption and the pollutions regulation. The objective of this paper is to compare the global and absolute thermal comfort indexes for two vehicles with different distribution air systems inside the car cockpit, one using only front air vents, and the other using both front and rear air vents. The methodology of calculus consists in using the 3D model of the interior vehicle, generally in a CAD format. Then, using a meshing software to create the finite element model of the interior surfaces inside the cockpit and the volume of internal air. Using the obtained finite element geometry, there will be conducted a Theseus FE calculus using the given boundary conditions. The results of the numerical simulation are presented in terms of graphs and figures and also PMV, PPD and DTS thermal comfort indexes. With the obtained results, we will then create the graphs that allows us to evaluate the global and absolute thermal comfort indexes. The results of the evaluation show us that the use of the method allow us to evaluate with a greater accuracy the thermal comfort for the whole vehicle, not only for each passenger, like the standard methods. This shows us that in terms of general and absolute thermal comfort, the vehicle that use front and rear systems is better than the version that use only a front system. The thermal comfort is an important aspect to be taken into account from the beginning of the design stage of a vehicle, by choosing the right air conditioning system. In addition, by using the numerical simulation, we are able to reduce the time needed for preliminary tests and be able to provide the vehicle to the market earlier, at a lower development cost.